Process of manufacturing gelatin capsules for use as bottle caps



Patented Jan. 31, 1928.

UNITED STATES PATENT OFFICE. I

WARREN WILKIE AND ALEXANDER D. WEBB, F DETROIT, MICHIGAN, ASSIGNORS TO PARKE, DAVIS & COMPANY, or can.

DETROIT, MICHIGAN, A CORPORATION OF MICHI- PROCESS OF MANUFACTURING GELATIN CAPSULES FOR USE AS BOTTLE CAPS.

Ho Drawing.

This invention relates to a process of manthe caps during the process of manufacture,

so as to raise the melting point of the gelatin to thereby eliminate the characteristic 1 stickiness of unmodified gelatin, and to render the caps immune to changes in temperature and climatic conditions, and thus im- 1 prove the articles produced. v Gelatin caps are extensively employed for the purpose of forming a permanent seal for bottles and the like. in practice a cap is selectedwhich is smaller in diameter than the neck of. the bottle to which it is to be applied, the cap being immersed in water for a predetermined period, during which time due to the hygroscopic nature of gelatin, the cap swells,'whereupon it maybe slipped over :0 the cork and the neck of the bottle and when it subsequently dries it shrinks into place around the cork and neck of the bottle, thus forming a finished and; permanentseal. In order to, overcome the stickinessinherent to an ordinary gelatin, it has been the practice in the past to subject these caps to a bath containing a certainamount of formaldehyde, or some like substance which reacts upon the gelatin and makes it insoluble, but this proc ess of treating the caps after they have been manufactured is quite laborious and technical, requiring very careful control ofthe proportions of the tanning agent and the temperature of the bath, in order to secure the proper degree of tanning. An undertreated cap would still be sticky when it is applied and would be affected by changes in temperature and humidity, such as unusual heat, moisture or dampnessafter it is applied to the bottle, while a cap wlnch received too much treatment would have its tensile strength destroyed and. would become very brittle and would be liable to crack or break 0E after itwas applied.

It is therefore the object of this invention to provide a process of manufacturing these bottle caps wherein'the gelatin is rendered sufliciently insoluble to withstand ordinary climatic changes of temperature and humidto ordinary gelatin, but at the same time not ity, and to overcome the stickiness inherent Application filed February 15, 1926. Serial No. 88,503.

such a degree where it would lose its tensile strength.

In practicing this invention a gelatin solutlon of the customary character and proportlons is employed which usually consists of gelatin and Water in the approximate proportlons of 30% gelatin and 7 0% water, the bath or solution being maintained at a tem- 60 perature of from 95 Fahrenheit to 120 Fahrenheit.

The capsule or cap is formed, in the usual or customary manner, on cooled molds or pins generally maintained at approximately 60 Fahrenheit or below.

When the proper temperature in the molds or pins has been attained, these molds are dipped, preferably a plurality at a time, into the gelatin solution or bath above referred to. The molds are then withdrawn and inverted or upturned to permit the gelatin solution which has adhered thereto, to distribute itself on the pins and to also permit the gelatin to lose its fluidity or, in other words, to change from a fluid to a plastic state. As the above method of manufacturmg capsules is widely practiced and well known, and forms no part of this invention, it has only been briefly referred to.

At this state of the process, the gelatin caps contain approximately 25% or more of water. The coated molds or pins are then reversed and plunged into a tanning solution for the purpose of raising the melting point of thegelatin. This tanning solution comprises a reagent possessing an aldehydic radical, together with glycerin and water, there being a predominance of water. This tanning solution may contain in addition to the glycerin and water, either formaldehyde, hexamethylene tetramine, tannic acid, aldol, paraformaldehyde, benzaldehyde or glucose. We have found that the above ingredients mixed in substantially the following proportions give satisfactory results:

Glycerin. Water.

Formaldehyde Hexamethylene tetramme. Tannic acid";

The proportions of water, glycerin and the tanning agent may vary, the relative proportions being selected according to existing conditions such as the percentageof the gelatin solution used for forming the caps, type of gelatin employed in the solution and length-of time the gelatin caps are left in the tanning solution, and the temperature of this tanning solution.

Afterheing immersed in the tanning solution for a short period the molds containing the gelatin caps are ren'ioved and placed in racks or the like which are then placed in adryi'ng room. A constant moderate temperature is maintained in the drying room as well as a moderately low degree of humidity, and the caps are allowed to remain in this drying room until their moisture content is reduced to approximately 20%, whereupon the caps will be rigid enough to strip from the molds or pins. v

After the caps have been "removed from the drying room the molds are run through the usual stripping machine where the caps are removed and the molds lubricated pre paratory to the "commencement of another cycle of operations. The caps which are stripped from'the molds present an uneven edge due to the contraction of the gelatin on the molds "during the drying. It is customary therefore to cut them to the proper length, whereuponthey are packed for ship ping or made ready for other use;

In applying to bottles or the like, gelatin caps made in accordance with this invention are immersed in cold water of a temperature preferably of 65 Fahrenheit for a period of approximately twenty minutes, whereupon they will swell or expand from approximately one and one-fourth to one and onehalf times their diameter. In this condition a cap may be readily slipped over the cork and neck of the bottle and will subsequently dry, forming a smooth and permanent seal. The effect of the tanning solution upon the gelatin cap or capsule is to raise the melting point of the gelatin so that ordinarily warm temperature, or dampness and moisture will have no effect upon it. It also overcomes the stickiness inherent in a plain gelatin cap, making it easy to handle and apply to a bottle.

WVhat we claim as our invention is:

1. In the process of manufacturing gelatinouscaps, that step which consists in treating the cap externally only with one of the higher aldehydes to raise the melting point of the outer skin.

2. In the process of manufacturing gelatinous caps, that step which consists in treatinrgthe caps externally only while in a plastic state containing a large per cent of water,

to raise the melting point of the outer skin. 3. In the process of manufactur ng gelatr nous caps, that step which consists in sub- Lew/sea jecting the outer surface only of the caps while in a semi-plastic state, to the action of a tanning solution.

4. In the process of manufacturing gelatinous caps, that step which consists in subjecting the outer surface only of the caps to the action of a tanning solution iuclu ling one of the higher aldehydes.

5. In the process of manufacturing gelatinous caps, that step which consists in dipping the caps while in a semi-plastic state to less than their full depth, in a bath contain ing a reagent possessing an aldehydic radical to treat the outer surface only.

6. In the process of manufacturing gelatinous caps, that step which consists in subjecting the caps while contained on the forming molds and while in a plastic state, to the action of a tanning solution.

' '7. In the process of manufacturing gelatinous caps, that step which consists of immersing the caps while in a plastic state, in a tanning bath while carried by the molds upon which the caps have been formed.

8. In the process of manufacturing gelatinous caps, those steps consisting in dipping previously cooled mold pins into a gelatin solution and immersing the caps thus formed while in a plastic state, containing 25% or more of water, in a tanning bath while they are still upon the mold pins.

9. In the process of mamifacturing gelatinous caps, that step which consists in treating the outer surface only of the cap to raise the melting point of the gelatin by iinmersing the same to less than its full depth in a tanning solution containing benzaidehydef 10. In the process of manufacturing gelatinous' caps, that step which consists in subjecting the outer surface of the caps, while in a semi-plastic state, to the action of a tanning solution containing one of the higher aldehydes to raise the melting point of the outer skin.

11. In the process of manufacturing gel'atinous caps, that step which consists in treating the cap to raise the melting point of the outer skin by dipping the same to less than its full depth in a tanning solution containing a reagent possessing an aldehydic radical, glycerine and water.

12. In the process of manufacturing gelatinous caps, that step which consists in subjecting the outer surface only of the caps, While in a plastic state, to the action of a. tanning solution containing from two-tenths of one percent to thirty percent of a reagent possessing an aldehydic radical, from one to twelve percent glycerine, and from sixty to ninety-live percent water.

13. In the process of manufacturing gelatinous caps, that step which consists in subjecting the outer surface only of the caps while in a plastic state, to the action ill) of a tanning solution containing approxiforming molds, to the actionof an agent for mately 0.2% to 1.25% of an aldehyde, 5% to rendering the skin surface thereof insoluble. 12% of glycerine, and 94.8% to 86.75% of In testimony whereof We aflix our signa- 10 Water. tnres.

14:- In the process of manufacturing gelatinous caps, that step which consists in WARREN WILKIE. subjecting the caps, while contained on the ALEXANDER D. WEBB. 

